Question 1,709 of 1,672
MLS-C01 Modeling Practice Question
A machine learning engineer is using Amazon SageMaker to train a model. The training data is stored in an S3 bucket encrypted with AWS KMS. The SageMaker training job fails with an AccessDenied error when trying to read the data. Which IAM policy addition should resolve the issue?
⚠ Common exam trap
Many exam-takers assume `s3:GetObject` is sufficient for reading encrypted objects, overlooking that KMS-encrypted S3 data requires explicit `kms:Decrypt` permissions on the execution role.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Add kms:Decrypt permission for the KMS key.
When an S3 bucket is encrypted with AWS KMS, the SageMaker training job's execution role must have the `kms:Decrypt` permission for the specific KMS key to read the encrypted objects. Without this permission, the job fails with an AccessDenied error, even if `s3:GetObject` is granted, because SageMaker must decrypt the data before reading it.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Add kms:Decrypt permission for the KMS key.
Why this is correct
Decrypt is required to read encrypted objects.
- ✗
Add s3:GetObject permission for the bucket.
Why it's wrong here
S3 read permission is usually already present; the error is KMS-related.
- ✗
Add kms:GenerateDataKey permission for the key.
Why it's wrong here
GenerateDataKey is for writing, not reading.
- ✗
Attach the AmazonSageMakerFullAccess policy.
Why it's wrong here
Full access may not include KMS permissions for custom keys.
Visual reference
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
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Last reviewed: Jun 24, 2026
This MLS-C01 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the MLS-C01 exam.
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